doubt in dialog programming

hi friends i am working on dialog programming.in the first screen i am entering the user data. after when i press 'display' button. it is not validating as per the user requirement. i mean in the initial screen i am entering the data like from and to date , employee code and division, etc. it must display the data i mean other data relevant up to the date entered. or as per the employee code. here i am writing the code like.

DATA: BEGIN OF lv_tour OCCURS 0,

ecode TYPE ztour1-ecode,

ename TYPE ztour1-ename,

edesig TYPE ztour1-edesig,

dcod TYPE ztour1-dcod,

date1 TYPE ztour1-date1,

date2 TYPE ztour1-date2,

vplac TYPE ztour1-vplac,

rmarks TYPE ztour1-rmarks.

DATA: END OF lv_tour.

in 100 PBO INPUT.

WHEN 'MODIFY'.

SELECT * FROM ztour1 INTO lv_tour WHERE

ecode = ztour1-ecode and dcod = ztour1-dcod.

append lv_tour.

endselect.

CALL SCREEN 101.

IN PBO MODULE status_0101 OUTPUT.

I AM ENTERING LIKE .

IF ok_code = 'MODIFY'.

LOOP AT SCREEN.

screen-input = 0.

MODIFY SCREEN.

ENDLOOP.

ENDIF.

ENDMODULE.

USING TABLE CONTROL.

PLEASE PROVIDE ME SOME SUGGESTOINS OR EXAMPLES.